Qantas Airways has grounded another two aircraft and warns of more to come as the ongoing strike by its engineers continues to cause a backlog on the maintenance of its fleet.
The grounding of the two Boeing 767s will see a further 80 domestic flights cancelled over the next month, mainly affecting services between the eastern states and Perth, the airline said in a statement.
The Oneworld carrier last week said it will ground four Boeing 737s and one 767 because of industrial action by the Australian Licensed Aircraft Engineers Association (ALAEA).
The action begain in September, with a ban on overtime work around the country and a "go-slow" approach, and the union has informed Qantas that it intends to keep this up until Christmas.
Since the union action began, over 60,000 passengers have been affected as 129 flights were cancelled and 321 flights delayed or brought forward, said Qantas. The grounding of the seven aircraft will force the airline to cancel around 500 flights and remove approximately 88,000 seats from sale over the next month, it added.
"If this overtime ban continues, we will be grounding even more aircraft," added Qantas CEO Alan Joyce.
"The ongoing action from the licensed aircraft maintenance engineers' union means we do not have the manpower to fulfil all of the necessary maintenance on our fleet of aircraft.
"The industrial action has caused a shortfall of more than 60,000 man hours of maintenance and this is increasing on a daily basis, forcing us to ground aircraft."
The strikes have resulted in Qantas's on-time performance slipping from 87% five weeks ago to 75% this week.
The airline said the ALAEA is still "demanding significant pay increases" and "guarantees that old work practices remain" despite new generation aircraft requiring less maintenance, less often. ALAEA's claim comes up to Australian dollar (A$) 165 million ($168.1 million) - plus A$95 million to build a new hangar.
"Unless the union drops its unreasonable demands, we are not going to get any closer to an agreement," added Joyce.
The airline is meeting with the Transport Workers' Union on 18 October, the ALAEA on 20 October and the pilots' union on 28 October.